What is why is he flirting with another girl in front of me?

I'm sorry to hear that you’re feeling uncomfortable with someone flirting with another girl in front of you. There could be several reasons for this behavior, and it's important to consider the context and dynamics of your relationship with this person. Here are some possibilities:

1. Lack of Awareness: They might not realize that their actions are making you uncomfortable. Some people naturally have a flirtatious demeanor, and it’s possible they are unaware of how their behavior is perceived.

2. Testing Boundaries: They could be testing boundaries to see how you will react. This might be a way to gauge your interest or feelings towards them.

3. Seeking Attention or Reassurance: Sometimes, people flirt with others to gain attention or validation. It may be a sign that they need reassurance about their own attractiveness or desirability.

4. Jealousy or Manipulation: In some cases, a person might flirt with others to provoke jealousy or manipulate emotions within an existing relationship. This is usually not a healthy behavior.

5. Just Friends or No Serious Intent: They might simply have a friendly relationship with the other person without any serious romantic intent.

6. Differences in Relationship Expectations: If you are in a relationship, it’s possible there might be differences in what each person considers acceptable behavior.

If their behavior bothers you, it might be helpful to have an open and honest conversation with them about how you feel. Communication is key in addressing misunderstandings and setting boundaries. Ensure you express your feelings calmly and clearly, and try to understand their perspective as well.